QueryString、Form表单的高效解析

HttpContent提供了ReadAsFormDataAsync()方法，实际开发中的拦截器、等常常产生重置Request流的需求，自定义解析方法如下，测试效率还算不错，字符串分切比原生读取快，自定义方法是线性时间算法，进一步提高的了效率。 

public static NameValueCollection FormResolveCustom(String reqStr)
{
    NameValueCollection form = new NameValueCollection(8);
    Char[] split = { '=' };
    String[] forms = reqStr.Split('&');

    for (Int32 i = 0; i < forms.Length; i++)
    {
        String[] kvp = forms[i].Split(split, 2, StringSplitOptions.RemoveEmptyEntries);
        if (kvp.Length == 2)
        {
            form.Add(kvp[0], HttpUtility.UrlDecode(kvp[1]));
        }
        else if (kvp.Length == 1)
        {
            form.Add(kvp[0], null);
        }
    }
    return form;
}

public static NameValueCollection FormResolvePro(String reqStr)
{
    NameValueCollection form = new NameValueCollection(8);
    Int32 eq = 0;
    Int32 at = 0;

    for (Int32 i = 0; i < reqStr.Length; i++)
    {
        if (reqStr[i] == '=')
        {
            at = i;
        }
        else if (reqStr[i] == '&' || i == reqStr.Length - 1)
        {
            Int32 valueLength = i - at - 1;
            if (i == reqStr.Length - 1)
            {
                valueLength++;
            }

            if (at > eq && valueLength > 0)
            {
                String name = HttpUtility.UrlDecode(reqStr.Substring(eq, at - eq));
                String value = HttpUtility.UrlDecode(reqStr.Substring(at + 1, valueLength));

                if (!String.IsNullOrWhiteSpace(name))
                {
                    form.Add(name, value);
                }
            }
            eq = i + 1;
            at = i + 1;
        }
    }
    return form;
}